Slide switch assembly with fixed terminal array preventing generation of pop noises

ABSTRACT

In a slide switch of the class comprising three terminal members arranged in the same plane on a casing and a first contact member carried by a slide member whereby the switching of a pair of circuits is effected by moving the slide member so as to cause the first contact member to bridge the center terminal member and either one of the outer terminal members, there are provided a pair of transition terminal members on the casing and a second contact member mounted on the slide member to cooperate with the transition terminal members. The main terminal members, transition terminal members and the first and second contact members are positioned with respect to each other such that the transition terminal members and the second contact member maintain a circuit in a closed state from an instant immediately prior to the disengagement of the first contact member from one of the outer terminal members to an instant immediately after the engagement of the first contact member with the other outer terminal member.

United States Patent [191 Nakasone [4 1 May 6,1975

[ SLIDE SWITCH ASSEMBLY WITH FIXED TERMINAL ARRAY PREVENTING GENERATION OF POP NOISES [75] Inventor:

[73] Assignee: Toko Incorporated, Tokyo, Japan [22] Filed: Nov. 8, 1973 [21] Appl. No.: 414,168

I-liroyuki Nakasone, Tokyo, Japan [30] Foreign Application Priority Data Nov. 11, 1972 Japan 47-113227 [52] US. Cl. 200/16 C; 200/1 R; 200/153 .1; 200/159 R [51] Int. Cl. H0111 15/08 [58] Field of Search 200/1 R, 11 R, 11 D, 16 R, 200/16 C, 16 D, 17 R, 153 J, 159 R, 252,

271-275, 293, 307,5 R, S E-5 EB; 307/112 Constable Garrett et a1.

'IIIIIIIIII' lanuzzi et a1 200/16 C Kennedy et al 200/16 D [57] ABSTRACT In a slide switch of the class comprising three terminal members arranged in the same plane on a casing and a first contact member carried by a slide member whereby the switching of a pair of circuits is effected by moving the slide member so as to cause the first contact member to bridge the center terminal member and either one of the outer terminal members, there are provided a pair of transition terminal members on the casing and a second contact member mounted on the slide member to cooperate with the transition terminal members. The main terminal members, transition terminal members and the first and second contact members are positioned with respect to each other such that the transition terminal members and the second contact member maintain a circuit in a closed state from an instant immediately prior to the disengagement of the first contact member from one of the outer terminal members to an instant immediately after the engagement of the first contact member with the other outer terminal member.

14 Claims, 26 Drawing Figures PATENTEUHAY 6i975 3.882.056

SHEEI 10? 3 PRIOR ART PRIOR ART in FIG. 3.

I7 15'] 15 [1 0 U D U U D 15 121 12h "b m m 1 FIG. 4.

SLIDE SWITCH ASSEMBLY WITH FIXED TERMINAL ARRAY PREVENTING GENERATION OF POP NOISES BACKGROUND OF THE INVENTION This invention relates to a slide switch or a muting switch capable of eliminating pop noises which are generated at the time of switching electrical circuits.

In a slide switch, particularly of the type including three juxtaposed terminal members wherein two adjacent terminal members are selected by a contact member for switching electric circuits, the construction of the switch is complicated because it utilizes a slide member. Further, when switching from one circuit to the other, there is a chance of opening the circuits, although momentary, whereby the current flowing through the circuit varies greatly, thus causing a noise. Considering a circuit as illustrated in FIG. 1 of the accompanying drawing, when a switch SW, is at the input a plurality of cascaded circuits 1, 2, 3 n, the noises generated at the time of transferring the switch SW, are amplified by amplifiers A, B and C, and the amplified noises produce large noises through a loudspeaker SP. Furthermore, large variations in the current are created at the time of switching and induce other types of noises. When a conventional push botton type slide switch having a construction as shown in FIG. 2 is used as the switch SW as the push button I is depressed to transfer the connection from one circuit to the other, a plurality of contact members 2, which are moved simultaneously, momentarily assume a position in which they do not engage either of the terminal members 3b and 3c before they come to bridge terminal members 30 and 3b.

To obviate this difficulty it has been proposed to combine a microswitch 4 with the slide switch shown in FIG. 2, the microswitch 4 being constructed and operated to open the circuit immediately prior to the switching of the circuits and close the circuit immediately after the transfer of the circuits. More particularly, a screw rod 9 adapted to push the push botton 8 of the microswitch 4 is secured to one end of a slidable member 7 guided by a chassis 6 to which the casing S of the slide switch is attached. However, such a construction is complicated because even when a single slide switch is used it is necessary to add the slidable member 7 associated with push botton 8 at the moment of being pushed thus increasing the dimensions and cost of manufacture.

SUMMARY OF THE INVENTION Accordingly, it is an object of this invention to provide an improved slide switch capable of eliminating the noise produced at the time of transferring the circuits without the necessity of providing an independent microswitch.

Another object of this invention is to provide an improved slide switch wherein main terminal members for transferring the circuits and transition terminal members for preventing noise are mounted in the same switch casing and are operated by a common slide member, thus simplifying the construction and operation of the slide switch.

According to this invention, there is provided a slide switch of the class comprising a hollow elongated casing, three juxtaposed terminal members secured on the inner wall of the casing, a slide member adapted to be reciprocated in the casing, and a first contact member carried by the slide member whereby the switching of a pair of circuits is effected by moving the slide member so as to cause the first contact member to bridge the center terminal and either one of the outer terminal members. According to the invention there are provided a pair of transition terminal members secured on the inner wall of the casing and a second contact member mounted on the slide member to cooperate with the transition terminal members, the three terminal members. The transition terminal members and the first and second contact members are positioned with respect to each other such that the transition terminal members and the second terminal member cooperating therewith maintain a circuit in a closed state from an instant immediately prior to the disengagement of the first contact member from one of the outer terminal members to an instant immediately after the engagement of said first contact member with the other outer terminal member.

According to other aspect of this invention there is provided a slide switch of the class comprising a hollow cylindrical casing, three juxtaposed terminal members secured on the inner wall of the casing, a slide member adapted to be reciprocated in the casing, and a first contact member carried by the slide member whereby switching of a pair of circuits is effected by moving the slide member so as to cause the first contact member to bridge the center terminal member and either one of the outer terminal members. There are provided, according to the invention, juxtaposed three transition terminal members secured on the inner wall of the casing, and a second contact member mounted on the slide member to bridge the center transition terminal member and either one of the outer transition terminal members, the terminal members, the transition terminal members and the first and second contact members being positioned with respect to each other such that the circuit through one outer transition terminal member, the second contact member and the center transition terminal member is broken before the circuit through one outer terminal member, the first contact member and the center terminal member is broken, and that the first contact member bridges the center terminal member and the other main terminal member before the second contact member comes to bridge the center transition terminal member and the other outer transition terminal member.

BRIEF DESCRIPTION OF THE DRAWINGS Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompnaying drawings in which:

FIG. 1 is a block diagram of one example of an electric circuit utilizing a slide switch;

FIG. 2 is a plan view, partly in section, of a prior art push button type slide switch;

FIG. 3 is a plan view of another type of conventional push button type slide switch;

FIG. 4 is a side view, partly in section, of a push button type slide switch embodying the invention;

FIG. 5 is a longitudinal sectional plan view of the slide switch shown in FIG. 4;

FIGS. 6a through 6e show diagrams useful to explain the operation of the slide switch shown in FIGS. 4 and FIG. 7 is a diagram showing the contact timing of the switch shown in FIGS. 4 and 5;

FIGS. 80 through 8c diagramatically show different arrangements of the transition terminal members;

FIG. 9 is a block diagram of an electric circuit to which the slide switch of this invention is applicable;

FIG. 10 is a plan view of an arrangement in which a plurality of slide switch units of this invention are juxtaposed;

FIG. 11 is a block diagram of an electric circuit to which a modified slide switch of this invention is appli cable;

FIG. 12 is a diagram showing the contact timing of the switch;

FIGS. 13a through 13a are diagrams useful to explain the operation of a modified slide switch; and

FIGS. 14a to 14c are partial sectional views showing still further modifications of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In one embodiment illustrated in FIGS. 4 and 5, in an terminal members 11a, 11b and llc which are used for switching a pair of circuits in cooperation with first contact member 13, and transition terminal members 120 and 12b which are wider than terminal members 11a, 11b and 110 are housed in a casing 10 of the slide switch. The terminal members 12a and 12b are used to maintain the circuit in the closed condition in cooperation with first contact member 13 for a short interval before and after the switching operation of the circuits, and hence are termed transition terminal members". The distance between the outer ends of the terminal members 120 and 12b is selected to be equal to that between the outer ends of the terminal members 11b and 110 and the inside ends of the terminal members 12a and 12b extend to one another. More particularly, at the time of the switching operation of the circuits, immediately prior to interrupting one, circuit that is immediately prior to the disengagement of contact member 13 from main terminal members 110 and 11b by the operation of a push button 14 and a slide member 15, transition terminal members 120 and 121; are connected in one circuit through a contact member 16 which is held in position by means of recess a and urged to the outside by coil spring 15b, whereas immediately after the other circuit is connected, that is immediately after the contact member 13 comes to bridge the main terminal members Ila and 110, the circuit through transition terminal members 12a and 12b is interrupted. A spring 17 is interposed between push button 14 and one end of the casing 10.

The operation of the slide switch shown in FIGS. 4 and 5 will now be described with reference to FIGS. 661-66. Under the condition shown in FIG. 6a, terminal members Ila and 1 lb are bridged or interconnected by contact member 13 for completing one circuit. As the slide member 15 is moved in the direction of an arrow A to switch the circuit, and when the condition shown in FIG. 6b is reached, main terminal members Il a and 11!; are still interconnected by contact member 13, while at the same time the transition terminal members 120 and 12b are interconnected by the contact member I6 to maintain the connection of one circuit. When the slide member 15 is further moved to the position shown in FIG. 6c, although the transition terminal members 120 and 12b are still interconnected by the contact member 16, main terminal members Ila, Ilb and Ilc for switching the circuit are disengaged from contact member 13. Then, in the condition shown in FIG. 6d, while the transition terminal members 120 and 12b are still being interconnected by the contact member 16, main terminal members Ila and 11c are interconnected by the contact member 13 to complete the other circuit. Finally, when the condition shown in FIG. 6e is reached, the transition terminal members 120 and 12b disengage the contact member 16 to interrupt the aforementioned circuit while main terminal members and 116 are bridged by the contact member 13 thereby maintaining the connection for the other circuit. At this time, the movement of the slide member 15 is prevented by means a lock mechanism (not shown) secured to said casing.

When the push button 14 is pushed and turned back to the original position with the spring, the process steps of switching the circuits are performed in the opposite order so that the circuit connections are switched from between main terminal members 11a and 116 to between main terminal members 110 and 11b. FIG. 7 shows this sequence of operation and the transition period. As can be noted from the graph shown in FIG. 7, transition terminals 12a and 1211 are interconnected from an instant immediately prior to the interruption of the connection betwen main terminal members 11a and 11b to an instant immediately after the interconnection of main terminal members 11a and 110.

In the embodiment described above, as can be noted from FIGS. 6a-6e three juxtaposed terminal members Ila, 11b and 11c are utilized to switch the circuits, and two wider terminal members 120 and 12b are used to maintain the circuit connection during transitions. However, it will be clear that relative arrangements of these terminal members other than that shown in the foregoing embodiment can also be used.

For example, as shown in FIG. 8a, the width of the transition terminal members 12a and 12b may not be increased. In the previous embodiment, the contact member 16 was constructed in the form of a letter M. In the modification shown in FIG. 8a, the contact member 16 is constructed in the form of an irregular letter M so that the width of the left hand projection is made larger than the width of the transition terminal members 12a or 12b. Alternatively, as shown in FIG. 8b the widths of transition terminal members 120 and 12b may be equal to the width of main terminal members 11a, 11b and 11c and the spacing between the transition terminal members 120 and 12b may be made equal to the spacing between main terminal members Ila and 11b and between main terminal members Ila and 116. In this case, the axial length of the contact member 16 is made equal to that of the contact member 13. Further as shown in FIG. 80, two of three main terminal members 11a, 11b and 11c for switching the circuits may be constructed also to act as the transition terminal members 12a and 12b. In this case, terminal members 12 and 12b are constructed to have steps as shown on the upper portion of FIG. 8c. In the embodiments illustrated in FIGS. 80 to 80, it is necessary that the position of the slide member I5 of the contact members 13 and 16 be so selected as to obtain the timing shown in FIG. 7. The slide switch of this invention provides a suitable transition period at the time of switching the circuits. FIG. 9 shows one example of the application of the slide switch, in which a contact SW, represents a switching terminal member corresponding to main terminals 11a, 11b and 110 shown in FIG. 4 whereas SW corresponds to transition or muting terminal members 120 and 12b. Although the switch SW is shown as being connected to a conductor between amplifiers B and C, it is to be understood that the switch SW, may be connected to a conductor interconnecting amplifiers A and B.

It is also possible to apply the invention to ganged switches. Thus, as shown in FIG. I0, transition terminals 12a and 12b of respective switch units are connected in parallel by lead conductors 18 and switch SW is connected between the amplifier B and C shown in FIG. 9. With this arrangment when any one of the ganged switches units is operated for switching the circuits, switch SW is always operated thus preventing any noise from occuring.

The foregoing embodiment is constructed 19b and 19c of both that switch SW is short circuited at the time of transferring switch SW but it is possible to connect switch SW directly in series with the circuit as shown in FIG. 11 so as to eliminate noise. The timing of the switching this case is shown in FIG. 12. Thus, switch SW is opened prior to the opening of switch SW and switch SW is closed only after the switching operation of switch SW, has completed. If switch SW is connected in a circuit having a low amplification it is possible to prevent the noise caused by the switching operation of switch SW FIG. 13 shows the construction and operation of such a switch. In FIG. 13, portions identical to those shown in 6 are designated by the same reference numerals. Thus, circuit switching main terminal members are designated by 11a, 11b and 11c while the transition terminal members of this embodiment are designated by 19a, 19b and 19c. As shown, the axial lengths L between the outer ends of the outer terminal members 11b and 11c and 19b and 19c both sets of the terminal members are equal, and the axial lengths or the effective contact widths of central terminal members 11a and 19a are also equal. However the width 1' of the outer transition terminal members 19b and 19c is about one half of that of the outsider terminal members 11b and lie. The relative positions of contact members 13 and 20 with respect to terminal members 11a, 11b and 11c and terminal members 19a, 19b and 19c are equal.

In the position shown in FIG. 13a, contact member 20 bridges the transition terminal members 19a and 19b whereas contact member 13 bridges the terminal members Ila and 11b. As the slide member 15 is moved in the direction of an arrow B to the position shown in FIG. 13b, the contact member is disengaged from terminal member 19b thus interrupting the connection between terminal members 19a and 19.5, whereas the contact member 13 is still bridging the terminal members 11a and 11b. In the position shown in FIG. 13c, both of contact members 13 and 20 engage only one terminal member. In the position shown in FIG. 13d, the contact member 20 engages only one terminal member 19a, whereas contact member 13 bridges terminal members 110 and 110, thus completing the other circuit. At the position shown in FIG. 1312, contact member 20 bridges terminal members 19a and 19c whereas contact member 13 bridges terminal members 11a and 110, thus completing the switching to the other circuit.

In this embodiment, the circuits are opened before switching thereof and the circuits are closed after completion of the switching of the circuits. For this reason, even when the switch is constructed to generate noise at the time of the switching operation, since the circuits are open at the time of switching, no noise will be created.

Since one end of terminal members 11a, 11b, 11c, 12a and 12b shown FIG. 4 are generally inserted in appropriate openings of a printed circuit board and are then soldered, by forming the pattern whereby the printed circuit to which the ends at the transition term inal members are to be connected constitutes the printed circuit for the switch SW it becomes possible to readily fabricate the transition circuit without the necessity of bonding the lead wires.

Although in the foregoing embodiment, only one set of the transition terminals 12a and 12b and cooperating contact member 16 is provided on one side of the set consisting of terminal members 11a, 11b, 11c and cooperating contact member 13, if required two of the former sets may be provided on the opposite sides of the latter set.

The terminal members utilized in this invention generally have a rectangular cross-sectional configuration as shown in FIGS. 5 and 6 and other figures, the configuration of these terminal members may be modified for improving the electrical contact and to assure smooth operation of the slide switch. For example, in the case shown in FIG. 14a the opposing ends of a pair of terminal members, for example 12a and 12b are slanted as at 21. In the case shown in FIG. 14b, in order to eliminate contact bounce an idle contact member 22 is positioned between a pair of terminal members 12a, 12b, whereas in the case shown in FIG. 14c the casing 10 of the switch is formed with an integral projection 10 positioned between adjacent terminal members 12a, 12b and having the same height as the thickness of the terminal members. These modifications improve the operation of the muting switch.

From the foregoing description it will be clear that the invention provides a novel slide switch capable of eliminating the noise which has been unavoidable in prior slide switches.

What is claimed is:

1. In a slide switch of the class comprising a hollow elongated casing, three juxtaposed main terminal members secured on the inner wall of said casing, a slide member adapted to be reciprocated in said casing, and a first contact member carried by said slide member whereby the switching of a pair of circuits is effected by moving said slide member so as to cause said first contact member to bridge the center main terminal member and either one of the outer main terminal members, the improvement which comprises a pair of transition terminal members secured on the inner wall of said casing and a second contact member mounted on said slide member to cooperate with said transition terminal members, said three main terminal members, said transition terminal members and said first and second contact members being positioned with respect to each other such that said transition terminal members and said second contact member cooperating therewith maintain a circuit in a closed state from an instant immediately prior to the disengagement of said first contact member from one of the outer main terminal members to an instant immediately after the engagement of said first contact member with the other outer main terminal member.

2. The slide switch according to claim 1 wherein said transition terminal members have a width larger than that of each of said main terminal members.

3. The slide switch according to claim 1 wherein the distance between the outer ends of said transition terminal member is equal to the distance between the outer ends of said outer main terminal members.

4. The slide switch according to claim 1 wherein each of said transition terminal members has the same width as each said three main terminal members and the dis tance between the outer ends of said pair of transition terminal members is equal to that between the outer ends of the outer main terminal members.

5. The slide switch according to claim 1 wherein each of said transition terminal members has the same width as each of said three main terminal members, said transition terminal members being positioned with respect to said three main terminal members such that said second contact members bridges said transition terminal members when said first contact member does not bridge the center main terminal member and either one of said outer main terminal members.

6. The slide switch according to claim 1 wherein an adjacent two of said three main terminal members are used to act also as said transition terminal members, said adjacent two terminal members having a stepped width.

7. A ganged slide switch assembly comprising a plurality of slide switch units according to claim 1, said units being mounted on a common chassis and the transition terminal members of the respective slide switch units being connected in parallel.

8. The ganged slide switch assembly according to claim 7 wherein said slide switch units are incorporated in a printed circuit board so that the transition terminal members of respective slide switch units are connected in parallel.

9. The slide switch according to claim 1 wherein in order to eliminate contact bounce an idle contact is provided between said transition terminal members.

10. The slide switch according to claim I wherein the opposing ends of said transition terminal members are slanted.

11. The slide switch according to claim 1 wherein 8 said casing is provided with an integral projection to prevent contact bounce between said transition termi nal members, and said projection has a height equal to the thickness of said transition terminal members.

12. In a slide switch of the class comprising a hollow elongated casing, three juxtaposed main terminal members secured on the inner wall of said casing, a slide member adapted to be reciprocated in said casing, and a first contact member carried by said slide member whereby switching of a pair of circuits is effected by moving said slide member so as to cause said first contact member to bridge the center main terminal member and either one of the outer main terminal members, the improvement which comprises juxtaposed three transition terminal members secured on the inner wall of said casing and a second contact member mounted on said slide member to bridge the center transition terminal member and either one of the outer transition terminal members, said three terminal members, said three transition terminal members and said first and second contact members being positioned with respect to each other such that the circuit through one outertransition terminal member, said second contact member and the center transition terminal member is broken before the circuit through one outer main terminal member, said first contact member and the center main terminal member is broken, and that said first contact member bridges said center main terminal member and the other outer terminal member before said second contact member comes to bridge the center transition terminal member and the other outer transition terminal member.

13. The slide switch according to claim 12 wherein the distance between the outer main ends of said outer terminal members is equal to the distance between the outer ends of said outer transition terminal members, the center transition terminal member has the same width as each one of said main terminal members, the outer transition terminal members have a width about one half of that of said central transition terminal member, and said first and second contact members have the same width.

14. The slide switch according to claim l2 wherein the opposing ends of said transition terminal members are slanted. 

1. In a slide switch of the class comprising a hollow elongated casing, three juxtaposed main terminal members secured on the inner wall of said casing, a slide member adapted to be reciprocated in said casing, and a first contact member carried by said slide member whereby the switching of a pair of circuits is effected by moving said slide member so as to cause said first contact member to bridge the center main terminal member and either one of the outer main terminal members, the improvement which comprises a pair of transition terminal members secured on the inner wall of said casing and a second contact member mounted on said slide member to cooperate with said transition terminal members, said three main terminal members, said transition terminal members and said first and second contact members being positioned with respect to each other such that said transition terminal members and said second contact member cooperating therewith maintain a circuit in a closed state from an instant immediately prior to the disengagement of said first contact member from one of the outer main terminal members to an instant immediately after the engagement of said first contact member with the other outer main terminal member.
 2. The slide switch according to claim 1 wherein said transition terminal members have a width larger than that of each of said main terminal members.
 3. The slide switch according to claim 1 wherein the distance between the outer ends of said transition terminal member is equal to the distance between the outer ends of said outer main terminal members.
 4. The slide switch according to claim 1 wherein each of said transition terminal members has the same width as each said three main terminal members and the distance between the outer ends of said pair of transition terminal members is equal to that between the outer ends of the outer main terminal members.
 5. The slide switch aCcording to claim 1 wherein each of said transition terminal members has the same width as each of said three main terminal members, said transition terminal members being positioned with respect to said three main terminal members such that said second contact members bridges said transition terminal members when said first contact member does not bridge the center main terminal member and either one of said outer main terminal members.
 6. The slide switch according to claim 1 wherein an adjacent two of said three main terminal members are used to act also as said transition terminal members, said adjacent two terminal members having a stepped width.
 7. A ganged slide switch assembly comprising a plurality of slide switch units according to claim 1, said units being mounted on a common chassis and the transition terminal members of the respective slide switch units being connected in parallel.
 8. The ganged slide switch assembly according to claim 7 wherein said slide switch units are incorporated in a printed circuit board so that the transition terminal members of respective slide switch units are connected in parallel.
 9. The slide switch according to claim 1 wherein in order to eliminate contact bounce an idle contact is provided between said transition terminal members.
 10. The slide switch according to claim 1 wherein the opposing ends of said transition terminal members are slanted.
 11. The slide switch according to claim 1 wherein said casing is provided with an integral projection to prevent contact bounce between said transition terminal members, and said projection has a height equal to the thickness of said transition terminal members.
 12. In a slide switch of the class comprising a hollow elongated casing, three juxtaposed main terminal members secured on the inner wall of said casing, a slide member adapted to be reciprocated in said casing, and a first contact member carried by said slide member whereby switching of a pair of circuits is effected by moving said slide member so as to cause said first contact member to bridge the center main terminal member and either one of the outer main terminal members, the improvement which comprises juxtaposed three transition terminal members secured on the inner wall of said casing and a second contact member mounted on said slide member to bridge the center transition terminal member and either one of the outer transition terminal members, said three terminal members, said three transition terminal members and said first and second contact members being positioned with respect to each other such that the circuit through one outertransition terminal member, said second contact member and the center transition terminal member is broken before the circuit through one outer main terminal member, said first contact member and the center main terminal member is broken, and that said first contact member bridges said center main terminal member and the other outer terminal member before said second contact member comes to bridge the center transition terminal member and the other outer transition terminal member.
 13. The slide switch according to claim 12 wherein the distance between the outer main ends of said outer terminal members is equal to the distance between the outer ends of said outer transition terminal members, the center transition terminal member has the same width as each one of said main terminal members, the outer transition terminal members have a width about one half of that of said central transition terminal member, and said first and second contact members have the same width.
 14. The slide switch according to claim 12 wherein the opposing ends of said transition terminal members are slanted. 